This invention relates to postage meter drive systems and, more particular, to means of driving the print drum and shutter bar of a postage meter such that the throughput of the postage meter mailing machine can be increased without necessitating an increases in the drive system operating speeds.
In a postage meter system of one type, a postage meter is provided that is separable from a mailing machine base. In this type of system, the mailing machine incorporates means for initiating print cycles of the postage meter, as well as driving means for driving the printing mechanism of the postage meter. In known equipment of the above type, the postage meter is provided with a printing drum which may incorporate either fixed or settable postage type. The drum is driven internally of the postage meter by a drive gear, the drive gear being adapted to be coupled to a driving gear in the mailing machine when the two units are intercoupled. The postage meter further incorporates a shutter bar adapted to be mechanically intercoupled to a shutter lever mounted in the mailing machine when the two units are interconnected. The shutter bar, or other suitable mechanical means coupled thereto, engage and prevent rotation of the drive gear, so that postage printing cannot be effectuated when the shutter is in its closed position. The shutter lever engages the shutter bar to effect the movement of the shutter bar to its open or release position upon the initiation of print cycle by suitable triggering means in the mailing machine. If the shutter bar of the postage meter is free to move, the shutter lever may thereby move the shutter bar out of blocking engagement with the drive gear. Conventionally, the mailing machine further incorporates a clutch operative by the shutter lever so that the driving gear in the base may be driven, to in turn drive the drive gear in the postage meter, only if the shutter bar is capable of being moved to its open position. The postage meter further incorporates various blocking, or interposing means, which prevent the operation of the shutter bar absent certain postage meter conditions, for example, the absence of adequate postage available as stored in a mechanical register in the postage meter itself, or the mounting of the meter on an improper base.
In systems of the aforementioned type, the mailing machine need not be secure from tampering, and may be a device sold as a retail item. The postage meter itself, however, is mechanically secure, i.e., it is enclosed in a secure housing so that the critical accounting and printing equipment cannot be tampered with, without rendering such tampering obvious to postal authorities upon inspection.
The advent of economical electrical control systems, especially microcomputer systems, has made it feasible to incorporate electronic accounting devices within the postage meter. Such electronic devices provide certain advantages, such as more rapid accounting of postage, to enable the use of the postage meters as a integrated part of high speed mail handling equipment. The electronic devices also may be economically produced providing the advantageous of light weight, reduced size and lower production cost of the postage meter devices. Further, electronic accounting means within the postage meter enables the meter to perform additional functions that are not otherwise readily achievable by mechanical means.
Electronic postage members of the above type are disclosed, for example, in U.S. Pat. Nos. 3,938,095, Check, Jr., et al. and 3,978,457, Check, Jr. et al.
A problem may arise in the use of an electronically accounting postage member in combination with high speed mail handling equipment, particularly high speed mailing machines. The problem arises from the accidental or intentional disruption of electrical power to the accounting registers of the postage meter during initiation of the printing cycle and subsequent to the release the postage member drive by the shutter bar. The printing cycle may then be completed without postage accounting as a result of power disruption to the electronic registers of the postage meter. U.S. Pat. No. 4,253,015, McFiggans et al., herein incorporated by reference, describes, among other things, a shutter bar, anti-reverse mechanism and register trigger arrangement which requires the completion of postage meter printing cycle after the print drum has been rotated beyond 10 to 20 degrees away from the home detented position notwithstanding disruption of electrical power to the postage meter.
It is noted that conventionally the drive actuation of the shutter bar and print drum are performed sequentially. That is, the shutter bar is actuated and delivered to its fully release position prior to actuation of the print drum.